MY employer, Paizo publishing, has a fiction line called Planet Stories, much of which is devoted to out-of-print works of classic pulp authors. One of these is Henry Kuttner, who I believe you’ll find listed in the “inspirational reading” section of the 1e DMG.
Kuttner’s The Dark World starts off quickly with WW2 veteran Edward Bond back in America shortly after the war, trying to piece together an 18-month blank spot in his memory… when a cowled child-like woman and a werewolf drag him through a realm of mist into another world. It turns out that Bond is actually Ganelon, a warlock and member of a dark coven in this parallel Earth, intent on subjugating the last free peoples and ruling in the name of a strange god named Llyr. A sorcerer of the free peoples switched Earth-Bond and Dark World-Ganelon and convinced Bond to help them against the coven. With two sets of memories in his head, Ganelon is unsure if he can trust his coven allies, and circumstances push him toward a path where he pretends to be the heroic Bond, allies with the free peoples, and plots to destroy the other members of the coven so he can rule unopposed.
It’s a really fast read, I burned through it in about an hour (though I’ll want to read it again soon to lock in some of the details). It addresses questions of memory, loyalty, and identity (much like Philip K. Dick’s story We Can Remember It For You, Wholesale, which was the basis of the movie Total Recall), how a unique event can create a divergent parallel reality, superscience explained as the supernatural, and even a Lovecraftian-ish creature that was once human but has evolved beyond time, space, and body. Not bad for 1946!
It was a fun read, and you can see how it influenced Gary Gygax in some ways (in particular, the rules for characters from Boot Hill or Gamma World crossing over into an AD&D game, and vice versa). It also gave me some inspiration for an upcoming project of mine, which I’ll announce shortly.
I strongly recommend you pick up this book. And if me saying it doesn’t convince you, here are some quotes from names you may recognize:
“I consider the work of Henry Kuttner the finest science-fantasy ever written.” –Marion Zimmer-Bradley
“A neglected master… a man who shaped science fiction and fantasy in its most important years.” –Ray Bradbury
“Looking back, Kuttner and Moore–and, specifically, The Dark World–were doubtless a general influence on my development as a writer.” –Roger Zelazny
Next up in my pulp reading is Robots Have No Tails, also by Kuttner and also from Planet Stories.